Air cleaner



H. F. FRUTH AIR CLEANER June 16, 1964 2 Sheets-Sheet 1 Filed July 22, 1960 j@ wf@ B2 @4M/7' H. F. FRUTH June 16, 1964 AIR CLEANER 2 Sheets-Shes?l 2 Filed July 22, 1960 United States `Patent O M 3,137,550 AIR CLEANER Hal F. Fruth, 5932 Morse Ave., Skokie, Ill. Filed July 22, 196i), Ser. No. 44,656 2 Claims. (Cl. 5S-131) The present invention relates to air cleaning apparatus designed to remove air borne particulates from air, the particulates being any and all air borne particles not in gas or vapor form. Such particulates may be borne by gases or vapors other than air and may be removed from such other gases and vapors in accordance with the invention in the same manner that the particles are removed from air.

One object of the invention is to provide air cleaning apparatus in which a most thorough and eicient removal of particulates from air is achieved by means of a new and improved cleaning structure which acts electrically and aerodynamically on the air in an improved manner to produce an increased incidence of impingement of suspended particles on the collecting surfaces of the collecting structures.

Another object is to provide new and improved air cleaning apparatus which utilizes an electric field to great advantage in effecting a permanent removal of particulates from an air stream in a manner which assures retention f the removed material by the particulate collecting structure independently of the electric field employed in initially precipitating them from the air by means of holding the particulates on and in air adhesive coating covering the collecting surfaces.

Another object is to provide air cleaning apparatus of the above character which is especially Well suited to remove particulates from air moved through the collecting structures in that the collecting structure incorporated into the air cleaning apparatus makes effective use of the velocity of the air to produce an aerodynamic action on the air which tends to bring suspended particulates into contact with the outer and inner collecting surfaces of the collecting structures.

Another object is to provide improved air cleaning apparatus in which the incidence of impingement of particulates on collecting surfaces is greatly increased by a highly advantageous correlation of aerodynamic and electrical forces applied to a stream of air by a new and improved collecting structure which makes a most advantageous use of electric potential in ionizing the air being cleaned in a manner which avoidsy undesirable production of ozone and nitrous oxide by providing many dark discharges from the internal points on the collector elements.

A further object is to provide improved air cleaning apparatus, as recited in the above objects, which is capable of collecting and retaining enormous quantities of contaminants without appreciable loss of air cleaning efliciency or pressure flow resistance build up.

Another object is to provide improved air cleaning apparatus, as set forth in the foregoing objects, which is capable of operating with great eflciency and elfectiveness when supplied with an electric potential, even though the potential may be poorly regulated, thus avoiding any necessity for providing an expensive power Supply unit capable of regulating the voltage with great accuracy.

Another object is to provide improved air cleaning apparatus in which'improved collecting elements used to physically collect and retain particulates, and functioning electrically and aerodynamically to increase the impingement of particulates on the collecting structures has a physical construction which is well suited for economical manufacture.

Other objects and advantages will become apparent from the following description of the exemplary embodi- 3,137,550 Patented June 1e, 1964 ment of the invention illustrated in the drawings, in which:

FIGURE l is a perspective view illustrating the housing 0f the air cleaning apparatus forming the illustrated ernbodirnent of the invention, a front panel of the housing and internal collector elements being removed to more clearly reveal collector element support structure within the housing;

FIG. 2 is a fragmentary sectional View, taken along the line 2--2 of FIG. l and illustrating the collector elements in place;

FIG. 3 is a fragmentary perspective view illustrating collector element. mounts within the housing;

FIG. 4 is a fragmentary sectional View, taken with reference to line 4 4 of FIG. 2 and illustrating the support of spaced collector elements by the collector element mounts;

FIG. 5 is a fragmentary perspective view illustrating the positional relationship of two adjacent collector elements;

lector element;

FIG. 7 is a sectional view of a collector element taken along the line 7--7 of FIG. 6; and

FIG. 8 is a diagrammatic illustration of the tiered collector elements together with the means used to apply an electric potential to the collector elements, and the means used for moving air through the collector elements.

Referring to the drawings in greater detail, the air cleaning apparatus forming the exemplary embodiment of the inventionillustrated comprises a housingl() defining an internal air-ilow space or channel 12 extending vertically through the interior of the housing air-space.

A current or stream of air to be cleaned is moved through the channel 12 by means of a fan or blower 14 mounted, as shown, in the top of the housing lllrand driven by an electric motor 16. The air moving fan and motor may be located on either side of the air cleaning elements so long as it moves air to be cleaned through the elements.

A. large access opening 18 in the front of the housing 10 is normally covered by a removable front panel (not shown).

Particulates suspended in the air moving through the channel 12 are removed from the air by a plurality of collector elements 20 supported Within the housing 10 in tiered, generally parallel relation to each other. The collectors 20 are charged to a high potential relative to each other and have a new and improved construction which applies to the air moving through the rchannel 14 and passing through the collectors mutually coordinated electrical and aerodynamic actions which cause a very high incidence of impingement of the particulates onsurfaces of the collectors. Thus, as will presently appear, the collectors 20 operate with great efficiency to initially collect particulates from the passing air stream and serve to retain them on the collectors independently ofthe electric potential used in initially removing the suspended particulates from the air. l

Each individual collector `element is substantially symmetrical with respect to a central plane of the collector which is generally flat or coplanar.l

The collectors 20 are'mounted in thehousing 10 on two series of tiered supports or shelf elements 22, 24 positioned support one collector element. Y

As illustrated, the series of supports 22'are grounded to the housing 10 by being mounted on the yphysical 'structure of the housing. As will presently appear, these FIG. 6 is a horizontal sectionall view of a typical col- A of dimpled aluminum foil.

grounded supports or mounts are connected to the grounded side of an electric power supply unit which applies a potential between adjacent collectors mounted in the housing. It will be observed that the collector supports or mounts 22 are disposed in horizontal positions, the individual supports 22 on each side of the housing being disposed in horizontally opposed relation to and in vertical alinement with the corresponding supports on the opposite side of the housing.

The other series of collector supports 24 are suspended in alternate, vertically spaced relation to the grounded supports 22, as shown in FIGS. 1 to 3. Preferably, each of the supports 24 is supported at opposite ends by reversely curved ceramic insulators 30. The reversely curved shapingk of the insulators 30 illustrated provides for supporting the collector mounts 24 near the collector mounts 22, while at the same time providing an effective length of each insulator which greatly exceeds the spacing of the adjacent mounts from each other.

The insulated mounts 24 are also disposed in horizontal positions, the mounts 24 on one side of the housing being paired against similar mounts on the other side of the housing.

, Preferably, each of the collector supports 22, 24 is shaped to dene a longitudinal channel 32 extending substantially the full length of the support and opening horizontally inward to receive one marginal side edge of a collector 2t), as will appear.

. A plurality of insulator blocks 34 are secured to the rear wall 35 of the housing 10 to be engaged by the collectors 20 supported in the insulated collector mounts 24.

The collectors 2i) are removably supported within the housing 10 to extend across the direction of air-flow through the space 12 by sliding the individual collectors horizontally into the opposed pairs of collector mounts 22, 24 in such manner that opposite side edges of each collector tit into the channels 32 ofthe supporting mounts. The collectors 20 supported in the insulated mounts 24- are charged to a potential of eight to ten thousand volts with respect to the adjacent collectors supported in the grounded channels 32. This is elected by means of a power supply unit 36 having a grounded side connected through a conductor 38 with the grounded channel supports 22, and a direct current output side connected through a conductor 4t) with the insulated collector supports 24.

Each of the collector elements 20 has a enestrated metal construction comprising a pervious metal core, 42, FIGS. to 7, sandwiched between two thin metal sheaths 44, 46. At the respective marginal side edges of each collector 20 the two sheaths 44, 46 are pressed firmly against the marginal edges of the core 42 and embraced to a sharp crest line. The individual sheath corrugations are transversely interrupted along the length of the corrugations to form a plurality of relatively short, longitudinal corrugation segments 52. Each corrugation segment 52 is folded inwardly toward the underlying core 42 at only one end of the segment, so that the segment has a pyramidal shape, as illustrated in FIGS. 5 to 7, which is inclined away from a perpendicular to the adjacent core 42. All of the pyramidal corrugation segments 52 of each collector sheath arerinclined in the same direction, as shown.` Moreover, the corrugation segments 52 formed in the sheathes 44, 46 on opposite sides of each collector sheath are inclined in the same direction. It will be understood that the word inclined here is used to describe the fact that the apex 54 of each pyramidal element 52 is otset from the base area of the pyramidal element. Thus, the elements can be regarded, for purposes of description, as being inclined or tilted with respect to the underlying collector core 42.

by a narrow metal binding 4S to form marginal edges 5t? along the four sides of the collectors which are adapted to fit slidably into the support channels 32 of the collector mounts 22, 24.

The pervious metal core 42 of each collector is preferably formed of expanded metal. The metal expanded to form the core is preferably aluminum foil.

The two sheaths 44, 46 on each collector 20 are also formed of metal foil, preferably aluminum. In order to provide maximum strength inthe structure of the sheaths 44, 46, and to maximize the particulate collecting capabilities of the sheaths, it is advantageous to form the sheaths This foil is dimpled or quilted by being passed through rollers, or the like. The sheaths 44, 46 are shaped into a form such that the sheath structure serves to produce both the desired electrical eiect and aerodynamic action by which the present invention achieves a highly eicient removal of air borne particulates.

structurally, each of the ltwo collector. sheaths 44, 46 are mirror images of each other. Each sheath is shaped 'to form a plurality of parallel corrugations, each of which projects outwardly from theunderlying pervious core 42 Vten thousand Voltsv with respect to Ycach other.

, ends of the deflectors or corrugation segments 52 in a manner such that the air-flow has a direction making an acute angle with the adjacent core 42 when it reaches the core. As the air emerges from the opposite side ofthe core it engages the interior inclined surfaces of the deflector elements 52 on the opposite side of the core and is directed away from the core at an acute angle with respect to the core and in a direction generally opposite Vfrom the angular direction in which the air approaches the core from the intake side.

The effect of this is to produce a turbulent scrubbing of the air against the interior and exterior surfaces of all the air deector elements 52 and to effect a turbulent movement of the air passing through the expanded metal previous core 42, all of which tends to bring suspended particulates into contact with surfaces of the collectors.

The collector corrugation segments or air-iiow detlectors 52, shaped into pyramidal form as described, project outwardly frorn adjacent the collector core 42 and denne apices 54 which are quite sharp. These apices are used to advantage as corona discharge points and in effecting ionization of the air moving through the collector space. Moreover, the apices are formed by the thin metal foil of the collector sheaths and are heated by the electrical discharge in use, as will presently appear,

which enhances the desired ionization of the air being Y cleaned.

In'order to make the most effective use of corona discharge Vin ionizing the air, the air detiector elements 52 are dimensioned so that the apices 54 are spaced at least three-eighths of an inch from the median plane of the underlying pervious core 42, and are spaced at least threefourths of an inch from each other. Also, the tiered collector mounts 22, 24 of the housing 1G are spaced so that the apices 54 on the adjacent collectors 20 have a spacing ranging from three-eighths to three-fourthsof an inch. 'Y

charges the adjacent collectors to a voltage of Veight to produces a highly effective ionization of the air passing between two collectors without generating ozone, nitrous oxide, or other noxious gases.

The combined electrical and aerodynamic action` of collectors effects a very thoroughcleaning of theV air by causing particles to contact all surfaces of the collector elements. Thus, the air is effectively vcleanedl of sus- As previously mentioned, the power supply unit 36 This l pended particles including particles of the following materials and sizes.

Table Particle sizes in microns Solids or dusts of organic or inorganic ma- Particulates which contact the collector surfaces are wet out and encapsulated and caused to adhere to the collector surfaces by means of an adhesive and absorbing coating on the surfaces which enables the collectors to collect and retain a very large volume of particulates without substantially diminishing the air cleaning ehiciency of the structure. The surfaces of each collector element 20 are substantially covered With a coating of a suitable water soluble adhesive which is generally nonvolatile and which remains fully effective over an indefinite period of time to Wet out and encapsulate particulates which are brought in Contact with the collector surfaces. Moreover, the coating of adhesive serves to retain the particulates on the collectors independently of the elecrtic voltage supplied to the collectors, thus preventing the collected materials from returning to the air, even though the forced circulation of air continues after the voltage is removed.

The capacity of the collectors 20 to collect and retain large volumes of air contaminants is greatly enhanced by the large volumetric capacity of each collector element to contain material within the spaces between the apices 54 on opposite sides of the collectors. Moreover, the pyramidal deflecting elements 52 on opposite sides of the collectors, together with the expanded metal core 42 provide a very extensive surface area to which an adhesive and absorbent coating is applied to collect and hold the particulate. The dirnpled surfaces of the sheaths 44, 46 provide pockets which tend to store uid for forming the adhesive coating.

Since the adhesive coating applied to the collectors 20 to adhere to and quench the particles is water soluble, the collectors 20 can be cleaned easily by removing the collectors from the housing and washing them in water.

It is also noteworthy that turbulent scrubbing of the air against the collectors 20 is enhanced by orienting adjacent collectors in the housing 10 so that the directions in which the air is directed by the adjacent collectors are turned at an angle of at least 90 with respect to each other. As shown, the collectors 20 are square. Hence adjacent collectors can be turned at angles of 90 or 180 With respect to each other, so that the deectors 52 on adjacent collectors are turned to a large angle with respect to each other.

An eii'lcient yet turbulent flow of air through the iowspace 12 is enhanced by air directors 60 connected between the grounded collector mounts 22 on one side of the housing 10 and an air directorv 62 connected between the insulating collector mounts 24 on the opposite side of the housing, as shown in FIGS. l and 2. The medial portions of the air directions 60 and 62 bow outwardly from the collector mounts intervening between the mounts at opposite edges of the individual air directors. Preferably, the last collector 20 in the ow stream of the air passing through the space 12 is grounded, as shown.

The invention is claimed as follows:

l. An air cleaning device comprising, in combination, a housing, a plurality of particulate collector elements each being formed of a fenestrated metal construction, two series of collector element mounts positioned in said housing in alternate spaced relation to each other to support said plurality of collector elements in said housing in spaced generally coextensive relation to each other, power supply means connected to said respective series of collector element mounts to eiect charging of alternate collectors on the mounts to a high voltage with respect to each other, each of said collector elements comprising a pervious metal core sandwiched between two metal foil sheaths, each of said sheaths being corrugated to dene a plurality of parallel corrugations each of which protrudes outwardly to a sharp crown, each of said protruding corrugations being transversely severed at longitudinal intervals therealong to form longitudinal corrugation segments, each of said corrugation segments being folded inwardly at one end yonly to form an air directing deflector means extending outwardly to a sharp point at an acute angle to the adjacent collector core, each said deilector means being of pyramidal shape having two sides and an open end, and a water soluble and substantially non-volatile particulate collecting film substantially covering the surfaces of each of said collector elements, said sharp points promoting a dark discharge between adjacent collector elements substantially free of generation of ozone and nitrous oxide.

2. An air cleaning device as set forth in claim 1 wherein successive collector elements are oriented so that the corrugations of one element are at right angles to the corrugations of adjacent collector elements, said air directing deilector means thereby being at right angles in successive collector elements, the deilector means of alternate collectors being parallel and opening in the same direction. l

References Cited in the iile of this patent UNITED STATES PATENTS 2,852,092 Fruth et al. Sept. 16, 1958 2,936,851 Cook May 17, 1960 FOREIGN PATENTS 67,668 Sweden Nov. 17, 1924 500,221 Great Britain Feb. 6, 1939 549,644 Germany Apr. 29, 1932 

1. AN AIR CLEANING DEVICE COMPRISING, IN COMBINATION, A HOUSING, A PLURALITY OF PARTICULATE COLLECTOR ELEMENTS EACH BEING FORMED OF A FENESTRATED METAL CONSTRUCTION, TWO SERIES OF COLLECTOR ELEMETN MOUNTS POSITIONED IN SAID HOUSING IN ALTERNATE SPACED RELATION TO EACH OTHER TO SUPPORT SAID PLURALITY OF COLLECTOR ELEMENTS IN SAID HOUSING IN SPACED GENERALLY COEXTENSIVE RELATION TO EACH OTHER, POWER SUPPLY MEANS CONNECTED TO SAID RESPECTIVE SERIES OF COLLECTOR ELEMENT MOUNTS TO EFFECT CHARGING OF ALTERNATE COLLECTORS ON THE MOUNTS TO A HIGH VOLTAGE WITH RESPECT TO EACH OTHER, EACH OF SAID COLLECTOR ELEMENTS COMPRISING A PEERVIOUS METAL CORE SANDWICHED BETWEEN TWO METAL FOIL SHEATHS, EACH OF SAID SHEATHS BEING CORRUGATED TO DEFINE A PLURALITY OF PARALLEL CORRUGATIONS EACH OF WHICH PROTRUDES OUTWARDLY TO A SHARP CROWN, EACH OF SAID PROTURDING CORRUGATIONS BEING TRANSVERSELY SEVERED AT LONGITUDINAL INTERVALS THEREALONG TO FORM LONGITUDINAL CORRUGATION SEGMENTS, EACHOF SAID CORRUGAITON SEGMENTS BEING FOLDED INWARDLY AT ONE END ONLY TO FORM AN AIR DIRECTING DEFLECTOR MEANS EXTENDING OUTWARDLY TO A SHARP POINT AT AN ACUTE ANGLE TO THE ADJACENT COLLECTOR CORE, EACH SAID DEFLECTOR MEANS BEING OF PYRAMIDAL SHAPE HAVING TWO SIDES AND AN OPEN END, AND A WATER SOLUBLE AND SUBSTANTIALLY NON-VOLATILE PARTICULATE COLLECTING FILM SUBSTANTIALLY COVERING THE SURFACES OF EACH OF SAID COLLECTOR ELEMENTS, SAID SHARP POINTS PROMOTING A DARK DISCHARGE BETWEEN ADJACENT COLLECTOR ELEMENTS SUBSTANTIALLY FREE OF GENERATION OF OZONE AND NITROUS OXIDE. 